Properties of the Number 78420

Seventy-Eight Thousand Four Hundred Twenty

Basics

Value: 78419 → 78420 → 78421

Parity: even

Prime: No

Previous Prime: 78401

Next Prime: 78427

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 2 ² × 3 × 5 × 1307

Divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 10011001001010100

Octal: 231124

Duodecimal: 39470

Hexadecimal: 13254

Square: 6149696400

Square Root: 280.035712008308

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the maximum plus the upper median minus the lower median minus the minimum of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one. A237249

Number of edges among all distinct circles that can be constructed from the 4 vertices and the equally spaced 4·n points placed on the sides of a square when every pair of the 4 + 4·n points are connected by a circle and where the points lie at the ends of the circle's diameter. A373108

a(n) = 400·n² + 20. A158601

Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 28. A31706

Number of hill-free Dyck paths of semilength n, having no UUDD's, where U=(1,1) and D=(1,-1) (a hill in a Dyck path is a peak at level 1). A105641

Number of (n+1) X (2+1) 0..2 arrays with the maximum plus the upper median minus the lower median minus the minimum of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one. A237243

Number of (n+1) X (4+1) 0..2 arrays with the maximum plus the upper median minus the lower median minus the minimum of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one. A237245

G.f. A(x) satisfies A(x/A(x)) = 1/(1-x). A88713

Numbers n such that h(n) = 3 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.) A78420